The trial of two men accused of murdering a Waikato publican more than 30 years ago is underway in the High Court in Auckland.

Chris Bush, 43, was drinking with staff when he was shot dead during a robbery at the Red Fox Tavern in Maramarua just before midnight on October 24, 1987.

News reports at the time of the murder said Bush was having a drink just after closing time when two heavily-disguised men burst into the bar, yelling "this is a hold-up".

Bush stood up to protect one of the barmaids when he was shot by a man with a double-barrelled shotgun.

The men then allegedly forced a staff member to search Bush's pockets for the key to the safe, then took about $20,000 before ransacking the bar.

Despite a number of suspects being questioned, no arrests were made and the case ran cold.

Tauranga man Mark Joseph Hoggart and another man, who has interim name suppression, were arrested in 2017, after the police re-opened the cold case.

Both men, who are aged in their early 60s, are charged with murder and aggravated robbery.

It's alleged the pair stole more than $36,000 in cash and cheques.

The trial before Justice Woolford and a jury of seven men and five women is scheduled to take up to 12 weeks.

The Crown expects to call more than 60 witnesses.

-Additional reporting by Sarah Robson/RNZ.