That work often involves handling client funds or credit arrangements, the board said.
Sinclair cannot get another licence for three years - the longest ban imposed since the licensing scheme came into force in 2012.
Registrar of Building Practitioner Licensing Paul Hobbs said the decision should send a clear message that dishonest or fraudulent behaviour is not acceptable in today's building industry.
"It's important consumers are able to feel confident in the integrity of their licensed builder, and decisions such as this one help protect the strength and reputation of the industry as it grows," Hobbs.
It is not the first time the board has taken action against builders.
Last year it cancelled the license of a Napier man for incompetent work and suspended another who took a "cavalier attitude towards building compliance".