MPs are required to register gifts and donations within 28 days of receiving them.
A No 10 spokeswoman said: “We sought advice from the authorities on coming to office.
“We believed we had been compliant, however, following further interrogation this month, we have declared further items.”
Lord Alli has previously bought clothes and glasses for Sir Keir, which have been listed on his entry on the register of MPs’ interests.
Most recently, the prime minister declared the fact Lord Alli had provided him with accommodation for several weeks, which is recorded as being worth more than £20,000.
In August, it emerged Lord Alli had been given a temporary Downing Street security pass despite having no formal government role.
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