Home Secretary Priti Patel has repeatedly refused to appear in front of a select committee to discuss the coronavirus outbreak.
Ms Patel has turned down four invitations since January, offering private briefings with ministers and officials instead.
A Home Office source said it was a “shame” the Home Affairs Committee’s chair had turned down the briefings.
Ms Patel says she would attend “towards the end of the month”.
BBC Home Affairs correspondent Danny Shaw described the letters between Ms Patel and Labour’s Yvette Cooper as “acrimonious”.
Ms Patel was appointed by Boris Johnson as home secretary in July 2019, but has only appeared in front of the committee once – in October.
The Home Office source said the offer was of “unprecedented access” to Home Office information including “classified and operationally sensitive briefings by ministers and officials”.
“Nonetheless, the home secretary has already offered to appear before the committee at the first mutually convenient date to update them on her work to keep the country safe during this unprecedented time.”
Ms Cooper wrote to the home secretary on 3 April.
She told Ms Patel the committee had set a date of 15 April to hear evidence from her, saying “there is no reason for further delay”.
But four days later, the home secretary responded, writing: “I am disappointed at the increasingly adversarial tone of our exchanges.”
Ms Patel instead said she would only appear “towards the end of the month”.
Ms Cooper has now written again, saying other secretaries of state have appeared regularly before other committees – but she has yet to receive a reply.