Drug maker Merck & Co will help produce rival Johnson & Johnson’s newly approved coronavirus vaccine in an effort to expand supply more quickly, a Biden administration official has confirmed.

The announcement came as the White House looks to speed up production of the single-dose vaccine.

Officials say J&J faced unexpected production issues with its vaccine and produced only 3.9 million doses before it received emergency use authorisation on Saturday.

The company says it is on track to deliver 100 million doses by the end of June.

The assistance from Merck is expected to help J&J meet its production commitments and expand supply further, but the administration did not provide specifics.

President Joe Biden is set to highlight the development in a speech on Tuesday afternoon.

The news was first reported by The Washington Post.