By 1980, the SIGWU had 10,000 members, half the country's workforce, and renamed itself the Solomon Islands National Union of Workers.

In 1996, the Australian Broadcasting Corporation described him as "the first ever [Solomon Islands politician] to go public about attempted corruption when he was a minister in the Sir Francis Billy Hilly Government.

He was offered $10,000 (SBD) by Tony Yeong, an employee of the Berjaya Group, one of Malaysia's biggest business empires.

As Minister of Commerce, he deported hundreds of Chinese illegal aliens sparking criticisms from fellow Members of Parliament.

And that is the use of so-called 'aid' funds by Republic of China (Taiwan) to manipulate and compromise the political processes in Solomon Islands".

Having become Executive Officer of Transparency Solomon Islands (an anti-corruption watchdog affiliated to Transparency International), Tuhanaku was particularly critical of Prime Minister Manasseh Sogavare's government, saying it had not addressed the country's social and economic problems, and had instead done nothing but "waste time with the Attorney-General and the Police Commissioner", in the Julian Moti affair.

Hemmer struck back by accusing Tuhanuku of having sexually assaulted a female manager, drawing media interest to the controversy.

She was credited for exposing the Sandline affair which resulted in the toppling of Prime Minister Sir Julius Chan's government in PNG and shook up the Papua New Guinea Defence Force.