"I have been offering some voluntary fast in preparation for Ramadan, and I've definitely felt a closeness to God that I haven't experienced before," said Mr Eastham, a storeman.
"I also think that fasting ... makes me more socially conscious, with the thirst and hunger, it makes you more aware of the plight of people who are less fortunate."
Shafiq ur Rehman, a missionary at the Baitul Muqeet Mosque, said the community was offering new converts encouragement and support.
The group were also inviting non-Muslims to a gathering at the mosque on June 18 to experience the fasting tradition in a bid to help people understand the significance of the practice.
"Fasting is one of the five basic pillars of the Islamic faith, and it strengthens our faith."
Mr Rehman said Ramadan was also a time when Muslims reconnected with the Koran, which they believe is the word of God.
Although Ramadan fasting is about refraining from eating, drinking and sex, Hazim Arafeh, president of the Federation of Islamic Associations, called for Muslims in New Zealand to also abstain from social media and the internet.
"That includes abstaining from excessive technology or mass advertising, from the anxiety to 'have' and of being attached to the mere temporal things we consume," Mr Arafeh said in a Ramadan letter to members.
"It is a time to be even more concerned for others, such as those in difficulty through poverty, or drugs, or other forms of harm."
Ramadan will run over the shortest winter days, meaning Muslims here will have one of the shortest fasting times in the world - just 11 hours each day compared to more than 20 hours in Europe or about 15 hours in the Middle East.
Fasting is compulsory for all Islam believers except for children and those who are sick.
When Ramadan falls is calculated by the lunar calendar, which means it moves about 11 days each year on the Gregorian date.
New Zealand has about 46,000 Muslims according to the 2013 Census figures.
Firoz Patel, secretary of the Aljamia Mosque in Ponsonby, said Muslims here will be notified tonight if a moon is sighted according to the Islamic sharia rules.
Ramadan
What is it?
Considered to be the holiest month by Muslims, when the Koran, the Islamic holy book, was revealed to prophet Muhammad.
When is it?
Depending on the moon sighting tonight, it could start tomorrow and will continue for 30 days until Tuesday July 5. Ahmadi Muslims will begin their observance tomorrow regardless.
Why do Muslims fast?
Fasting is one of the five pillars of Islam, and fasting during Ramadan is obligatory. No food or drink is consumed in daylight hours.