Embattled ACT MP John Banks has admitted he failed to declare a $1000 gift hamper he received from piracy accused Kim Dotcom.

Mr Banks and his wife received the hamper while staying at the Grand Hyatt hotel in Hong Kong over Christmas last year, reportedly at the suggestion of Dotcom who helped him secure a discount.

The multi-millionaire rents the hotel's top floor.

Dotcom is under house arrest in New Zealand facing internet piracy charges.

Mr Banks says he gave away the hamper - containing hand-made chocolates, truffle pate, whisky and champagne and valued at more than $1000 - to hotel staff.

He failed to declare the gift to parliament's register of pecuniary interests, as is required for all gifts worth more than $500, saying he did not believe it was worth that much.

But in a statement to 3News on Wednesday, he said he would now declare the gift.

Mr Banks previously brushed off allegations that Dotcom helped him secure a discounted room at the hotel, saying he haggled a deal.

But an email from hotel staff to Dotcom following Mr Banks' stay tells a different story.

"They had a great stay and asked me to pass on their thanks to you for your hospitality and kindness," a staff member wrote.

"In the end Mr Banks was more comfortable paying for everything. He paid himself for a Regular room and I upgraded him to a Grand Harbour Delux room with our compliments."

Mr Banks has spent weeks in the spotlight over his relationship with Dotcom.

Police are investigating claims Mr Banks knew of donations made by Dotcom and SkyCity to his failed mayoral campaign in 2010, but declared them as anonymous.

Mr Banks had previously offered help to Dotcom as he sought to buy the $30 million Chrisco mansion in Coatesville, north of Auckland.

Mr Banks also asked Dotcom for a donation to the ACT Party before last year's election, promising to be "a very good friend" once he was in parliament, but was told to "go get f*****, the New Zealand Herald reports.