Labour has called on the beleaguered housing secretary, Robert Jenrick, to explain a ministerial meeting with a “family friend” who had a financial interest in the future of a rival mining project that Jenrick was overseeing.

The Guardian revealed this week that Jenrick met the Israeli billionaire Idan Ofer while the then exchequer secretary to the Treasury was considering a request for financial support from Sirius Minerals for a mining project that would have rivalled Ofer’s own firm Cleveland Potash.

A spokesperson for Jenrick said on Friday that Ofer was a “family friend” and that the minister had notified officials, who advised him to step back from the decision on Sirius.

But the spokesperson did not say when Jenrick recused himself and the Guardian understands he retained oversight of Sirius’s request for support for at least six months after the meeting.

Steve Reed, the shadow communities secretary, said: “Mr Jenrick must now tell us whether he declared his friendship with Mr Ofer to officials prior to the meeting, why he did not immediately step back from making the decision and what further discussions he had with Mr Ofer.

“It’s time for some honesty. Mr Jenrick must come to the House of Commons to explain exactly what he’s been up to because the public are now worried that a new era of Tory sleaze has begun in earnest.”

A spokesperson for Jenrick said: “Whilst exchequer secretary, Mr Jenrick met with a number of stakeholders to discuss electric vehicles and charge point technology.

“This included a meeting with Mr Ofer, who has substantial experience in the industry. Officials from [the Treasury] attended those meetings and they were disclosed in his ministerial transparency data in the usual way.”

Earlier this week, Ofer told the Guardian he had met Jenrick to discuss the post-Brexit business climate. He said he could not recall if they had talked about the Sirius Minerals mining project, but that it would have been “touched on only briefly” if so.

“Mr Jenrick recused himself from consideration of issues around Sirius Minerals,” the minister’s spokesperson said.

“He did so before ministerial decisions were taken on the project, which I understand were taken after he had left HM Treasury in any case. Mr Ofer is a family friend. Mr Jenrick raised this with officials and voluntarily recused himself on their advice.”

Labour has already reported Jenrick to parliament’s watchdog over separate claims about his relationship to the Conservative donor Richard Desmond while serving in his current role as housing secretary. Jenrick appeared to have acted “on direct instruction” from Desmond, Labour said, saving the property and media tycoon tens of millions of pounds on a £1bn property development in east London.

The cabinet minister has so far had the support of Downing Street over his ties to Desmond but questions about his previous role at the Treasury will increase the pressure.

As exchequer secretary, he presided over Sirius Minerals’ application for financial support for at least six months after meeting with Ofer, before handing responsibility for the project to Liz Truss in early 2019.

In March 2019, one of Ofer’s other UK firms, the Mayfair-based Quantum Pacific UK Corporation, donated to the Conservative party for the first and only time, giving the party £10,000 in March 2019.

Ofer has said the request for the donation came at the behest of Conservative Friends of Israel and was not discussed with Jenrick, who is a member of the group.

Six months later, in September 2019, Sirius Minerals revealed that the government had refused to provide financial support, a decision that in effect left the company on the brink of financial collapse.

Sirius was eventually bought out in a cut-price deal by the mining firm Anglo American in January 2020, wiping out the shareholdings of hundreds of small investors. Some lost most of their life savings because of the collapse, which Sirius Minerals said would not have happened if the government had supported the project.

• This article’s headline was amended on 27 June 2020 to better reflect the text of the story.