Debate about independence has raged for decades but legal complications mean plans to take the issue to a vote have stalled several times.

Former senator Eddie Duenas said a self-rule plebiscite was long overdue and should be held during a gubernatorial election expected next year.

"We have been driving but we don't know where we're driving to and how far we will go," he told a recent meeting of Guam's decolonisation commission in the capital Hagatna.

"We just keep driving and driving. It's annoying."

Guam has been an unincorporated territory of the United States since 1898, meaning its 160,000 inhabitants are US citizens but have limited rights.

They cannot participate in US elections and Guam's sole representative in the US Congress does not get to vote on legislation.

The United Nations lists Guam as one of only 17 remaining colonies worldwide, something Governor Eddie Calvo wants remedied.